#!/usr/bin/env python
# -*- coding: utf-8 -*-
# @Time    : 2020/3/13 19:37
# @Author  : Roohom
# @Site    : 
# @File    : day15.py
# @Software: PyCharm
"""
排序算法
"""


def selecet_sort(orign_items, comp=lambda x, y:x < y):
    '''简单选择排序'''
    items = orign_items[:]
    for i in range(len(items)-1):
        min_index = i
        for j in  range(i+1, len(items)):
            if comp(items[j], items[min_index]):
                min_index = j
            items[i], items[min_index] = items[min_index], items[i]
        return items


def bubble_sort(orign_items, comp=lambda x, y:x >y):
    """高质量冒泡排序（搅拌排序）"""
    items = orign_items[:]
    for i in range(len(items)-1):
        swapped = False
        for j in range(i, len(items)-1 -i):
            if comp(items[j], items[j+1]):
                items[j], items[j-1] = items[j+1], items[j]
                swapped = True
        if swapped:
            swapped = False
            for j in range(len(items)-2-i, i, -1):
                if comp(items[j-1], items[j]):
                    items[j], items[j-1] = items[j-1], items[j]
                    swapped = True
        if not swapped:
            break
    return items


def merge_sort(items, comp=lambda x, y: x <= y):
    """归并排序(分治法)"""
    if len(items) < 2:
        return items[:]
    mid = len(items) // 2
    left = merge_sort(items[:mid], comp)
    right = merge_sort(items[mid:], comp)
    return merge(left, right, comp)


def merge(items1, items2, comp):
    """合并(将两个有序的列表合并成一个有序的列表)"""
    items = []
    index1, index2 = 0, 0
    while index1 < len(items1) and index2 < len(items2):
        if comp(items1[index1], items2[index2]):
            items.append(items1[index1])
            index1 += 1
        else:
            items.append(items2[index2])
            index2 += 1
    items += items1[index1:]
    items += items2[index2:]
    return items


def seq_search(items, key):
    """顺序查找"""
    for index, item in enumerate(items):
        if item == key:
            return index
    return -1


def bin_search(items, key):
    """折半查找"""
    start, end = 0, len(items) - 1
    while start <= end:
        mid = (start + end) // 2
        if key > items[mid]:
            start = mid + 1
        elif key < items[mid]:
            end = mid - 1
        else:
            return mid
    return -1

